Manuka honey from New Zealand, renowned for its wound healing properties, shows potential against bacteria responsible for respiratory infections, including antibiotic-resistant strains. This finding comes from recent research conducted by Aston University, highlighting that the honey’s antibacterial effects stem from a synergy of methylglyoxal (MGO) and other compounds within the honey matrix.
Allcott et al. Increased UMF grades in Manuka honey are linked to stronger antibacterial activity, indicating other factors beyond sugar content and MGO. Image credit: Estelle Heights.
“Manuka honey, derived from Leptospermum scoparium, has gained significant attention in New Zealand due to its broad-spectrum antibacterial properties,” stated Jonathan Cox and his research team from Aston University.
“Unlike other types of honey, the antibacterial properties of Manuka honey primarily arise from non-peroxide mechanisms.”
“Commercial Manuka honey is classified using the Unique Manuka Factor (UMF) grading system, which validates authenticity and the presence of essential marker compounds.”
“The UMF grading system is independently verified and includes tests to ensure no adulterants are present, along with assessments for MGO, leptosperin, and dihydroxyacetone.”
“UMF grades typically range from 5+ to 20+ or above, with higher grades indicating elevated concentrations of MGO.”
“However, it remains uncertain whether increasing UMF grade consistently correlates with enhanced antimicrobial activity.”
The researchers collaborated with honey producer Comvita to analyze five grades of Manuka honey against four pathogens (both methicillin-sensitive and methicillin-resistant), which can lead to severe respiratory infections, including Staphylococcus aureus (MRSA), Klebsiella pneumoniae, and Pseudomonas aeruginosa.
All honey grades inhibited bacterial growth, with a stronger effect observed as UMF grade increased.
Notably, two strains of staphylococcus, including drug-resistant MRSA, were especially susceptible, requiring significantly less honey to inhibit their growth compared to two more resilient Gram-negative bacteria.
The central question addressed by researchers was why Manuka honey exhibited greater efficacy than regular honey, despite both being concentrated sugar solutions that can dehydrate bacteria via osmotic stress.
To investigate this, they compared Manuka honey with a sugar solution that mirrored its carbohydrate composition.
Results indicated that honey suppressed bacterial growth much more effectively than sugar alone, demonstrating that osmolarity alone does not account for its efficacy.
When solutions containing MGO at concentrations found naturally in honey grades were created, they showed some antibacterial effects but were consistently less effective compared to whole honey.
This difference was particularly evident for two Gram-negative bacteria, which the MGO-only solution struggled to inhibit even at high doses.
Overall, the study suggests that Manuka honey’s antibacterial potency is a result of multiple components, including sugars, MGO, and other largely uncharacterized compounds within the honey matrix, rather than a singular factor.
“Manuka honey is often simplified to a single compound, MGO, but our findings reveal a more intricate story,” Dr. Cox expressed.
“Premium Manuka honey seems to derive its antibacterial effect from a combination of several interacting components, and understanding these interactions may lead to new strategies for combating infectious diseases amid rising antimicrobial resistance.”
“The complex nature of Manuka honey may provide a powerful solution to the global antimicrobial resistance crisis. We just need to discover how to utilize Manuka honey effectively.”
“Manuka honey has long been celebrated for its unique antibacterial characteristics,” added Dr. Jackie Evans, Chief Scientific Officer at Comvita.
“This groundbreaking study illustrates that MGO is only a fraction of the full story.”
For more information, view the study results published in Microbiology.
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Gemma J. Alcott et al. 2026. The unique antibacterial activity of Manuka honey, as determined by its UMF, cannot be attributed solely to sugar or methylglyoxal. Microbiology 172 (8); doi: 10.1099/mic.0.001746
Source: www.sci.news
